Lecture on Adding Enthalpy

[Karen Harrison 1L]

Hello,
Why did Dr. Lavelle add the 2NO₂ and not the 2NO on both the left and right sides of the chemical reaction shown in today's lecture (timestamp 12:00)?
Thank you!

[Dana Sorensen 1C]

The 2NO cancelled out on either side, the reactions N2 + O2 -> 2NO added with 2NO + O2 -> 2NO2 creates the net reaction N2 + 2O2 + 2NO -> 2NO2 + 2NO so the 2NO was omitted as it is both a reactant and product.

[405669838]

The 2NO on each side of the equations cancels out when the 2 equations are added, so they are not included in the new equation. 2NO2 remains because it does not get cancelled out.

[Aanjaneyaa]

When adding equations, if there is the same compound on the reactants and the products sides, then it gets cancelled out. That is the case for 2NO, but not for 2NO2.

[Gianna Greco 1G]

Hi! The 2NO was cancelled out because it was both a reactant and a product.

[Tammy Shen 2L]

2NO is canceled, as it appears on both sides of the equation. It is both a reactant and product, so it cancels when we plug it into the bond enthalpy equation.

[Eric Sun 2G]

When we add the two equations, the same compound of 2NO was found in both the reactants and products. Just like in algebra, adding the same value to both sides of the reactants and products essentially just cancels out the compound.